Commutator-brush



(No Model.)

0. L. GOFPIN.

GOMMUTATOR BRUSH.

No. 475,668. Patented May 24, 1892.

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UNITED STATES PATENT J OFFICE.

CHARLES L. COFFIN, OF DETROIT, MICHIGAN.

COMMUTATOR-BRUSH.

SPECIFICATION forming part of Letters Patent No. 475,668, dated May 24, 1892 Application filed September 5, 1891. Serial 110,404,844. (N0 model.)

To all whom it Hwy concern.-

Be it known that 1, CHARLES L. 00mm, of Detroit, in the county of \Vayne and State of Michigan, have invented a new and useful Improvement in Commutator-Brushes, of which the following is a specification.

My invention consists in an improvement in commutator-brushes for dynamos or electric motors hereinafter fully described and claimed.

Figure 1 is a plan view of a commutator, showing one brush and a portion of the brushholding mechanism; and Fig. 2 is a detail perspective View of a brush embodying my in- Vention.

O represents the commutator of a dynamo or motor; R, the rocker-arm which carries the brush-holders, one of which is shown at H; and S represents a set-screw, which clamps the brush in the holder H. All of these parts are old and well known and form no part of my invention.

B represents my improved brush, consisting' of a thin sheet of metal, preferably copper, perforated as shown at I. The perforations P are preferably staggered, as shown, as this causes the end of the brush to wear better; but they may of course be in regular lines. The perforations P permit the access of air to theinterior of the brush and prevent the overheating, which is such a great defect in brushes as ordinarily made.

In practice each brush will be made up of a number of thin perforated strips, as shown in Fig. 2.

What I claim as my invention, and desire to secure by Letters Patent, is

1. A commutator-brush consisting of a strip of perforated sheet metal.

2. A comm utator-brush consisting of strips of perforated sheet metal.

CHARLES L. COFFIN. Witnesses:

HENRY B. Lorr-rnor, GEO. H. LOTI-IROP. 

